Rick from Idaho said that differentials catch fire after fishing trips. There may be a connection.
Is he towing a boat?
Is he backing the boat into the water?
Is he submerging the dif?
A differential that is warm from many miles of travel, submerged in cool water, will cool quickly, suck in water and compromise gear lubrication.
…just a theory.
I had a similar problem with a Volvo V70 wagon years ago. I bought the car used and the first three times I went on any trip of considerable length, I fried the viscous coupling for the four wheel drive mechanism. Fortunately I had an extended warranty on the car, so the repairs didn’t cost me a dime. The dealer ended up putting three new couplings into this “certified” used car before they realized the heat shield from the muffler was missing.
The muffler sits directly under the coupling, so each time I went on a long trip, enough heat was applied to the coupling to fry the oil and ruin the gears.
Perhaps this is the same thing happening to Rick’s car.